枚举与集合

（1）Dictionary
private Dictionary<Card.Values,Player> books;
foreach (Card.Values value in books.Keys) {
                //Dictionary的使用
                //books[value]得到Player
                whoHasWhichBooks += books[value].Name +
                    " has a book of " + value;
            }

foreach (Card.Values value in books.Keys) {
                string name = books[value].Name;
                if (winners.ContainsKey(name))
                {
                    winners[name]++;
                }
                else {
                    winners.Add(name,1);
                }
            }